Patent Literature 1 discloses a sealed storage battery that includes a housing composed of two metal sheets also serving as electrodes, as illustrated in a perspective view of FIG. 1 and a cross-sectional view of FIG. 2 taken along the line A1-A2 of FIG. 1. At least one of the metal sheets has a recessed portion having a flange portion at its periphery. The two metal sheets are sealed with an adhesive film.